1. Field of the Invention
The present invention relates to an adjusting device for axial and radial piston machines, which includes an electrical servomotor, a drive, and a coupling which is arranged intermediate the drive and the setting or adjusting element for the machine.
2. Discussion of the Prior Art
Adjusting devices of that type are utilized for the varying or regulation of the volumetric setting in hydrostatic units, in which a lifting member of the hydrostatic unit is positionally displaced through the utilization of a screw spindle adjusting device. Besides a manual adjustment through the intermediary of a hand wheel it is hereby usual to provide for an adjustment by means of an electric motor which includes a reduction drive (compare with Thoma, "Hydrostatiche Getriebe", pages 100 and 101), wherein there is usually provided a coupling at the power output side of the drive for overload protection. Such drives can be constructed as starwheel drives, bevel gear drives, or planetary gear drives (refer to German Laid-open Patent Application No. 23 44 336).
In the practice the most differing adjusting speeds are required, wherein the change in the adjusting speeds can also be initially required, in essence, in machines which are in current use. Thus, in the common adjusting devices is usual to provide drives with a plurality of transmission stages which results in a higher requirement for components and a considerable constructional parameter, so that the building on of the drive arrangement for the adjusting device is carried out at the one side on the machine member, thereby rendering the entire arrangement bulky. The exchange of the electrical servomotor and/or that of the drive is a difficult labor which, particularly in dangerous surroundings, can lead to lengthy inoperative or down-time periods.